WO2010026458A1

WO2010026458A1 - Chest drain

Info

Publication number: WO2010026458A1
Application number: PCT/IB2009/006669
Authority: WO
Inventors: Dirk Christiaan De Villiers; Nicolaas Hendrik Smit
Original assignee: Dirk Christiaan De Villiers; Nicolaas Hendrik Smit
Priority date: 2008-09-04
Filing date: 2009-08-28
Publication date: 2010-03-11

Abstract

A chest drain is provided of the type comprising a liquid collection chamber (1 ) having an inlet (2) for connection to a chest drain tube (3) and a vent outlet (14) for operative venting to atmosphere or for connection to a source of vacuum. A one-way valve (20, 21 ) is provided for preventing backflow of fluids from the liquid collection chamber by way of the inlet. The inlet to the chest drain has connected to it a variable volume elastomeric bulb (4) in communication with the interior of the inlet and any tube supplying same. Preferably, the elastomeric bulb is connected in line with the inlet and tube supplying same. The elastomeric bulb is preferably selected such that it can be maintained in a collapsed condition by a vacuum of about 20 cm of water.

Description

CHEST DRAIN

FIELD OF THE INVENTION

This invention relates to a chest drain for draining fluids from the thoracic space within which the lungs and heart are retained.

More particularly, the invention relates to a chest drain used to drain fluids from the space around the heart, around the lungs and from in between the lungs.

BACKGROUND TO THE INVENTION

The breathing process is dependent on the existence of a partial vacuum in the pleural space within the chest cavity so that the lungs can expand and contract with the chest cavity when air at atmospheric pressure fills the lungs. This partial vacuum can be disturbed consequent on disease or following surgery or injury and pneumothorax (presence of air) or haemothorax (presence of blood) may develop in the pleural space (potential space around the lungs). These gases and liquids need to be removed so that the partial vacuum can be restored and normal breathing resumed. Also, excessive blood / exudates are drained from the mediastinum (space between the lungs) and pericardial space (potential space around the heart) after thoracic and cardio thoracic surgery. Such fluid removal is typically carried out by inserting a thoracic catheter into the affected space and connecting the catheter to a chest drain.

One of the oldest chest drains is the underwater drain comprising a simple bottle into which a rigid tube is inserted through a cap. The rigid tube is connected by way of a flexible tube, to a catheter inserted into the pleural

P 1886PC00SinapiChestDraιn space or mediastinal space. The rigid tube has its lower end immersed in water or saline solution to a depth that can normally be varied and is typically about 2 cm. The bottle must be kept upright at all times. This, in effect, creates a one way valve which prevents air from flowing back to the chest cavity. A vent tube also passes through the cap of the bottle and may either be open to atmosphere or be connected to low-pressure suction. An advantage of the underwater drain is that the liquid level in the rigid inlet tube changes during expiration and inspiration and gives a good indication of the pressure in the pleural space. Another advantage of the underwater drain is that bubbles of gas exiting the rigid inlet tube can be observed.

A major disadvantage of the underwater drain is, however, that the pressure exerted on the pleural space will vary with the depth of water in the bottle as liquids accumulate in it unless the inlet tube is constantly moved upwards to compensate for drained liquids entering the bottle. Also, the system is bulky and thus not very mobile; it ceases to function if overturned; and it normally requires a long flexible tube to connect the bottle to the catheter or chest tube. A long connecting tube is subject to forming kinks that could trap liquids and cause an increase in the pressure required to discharge fluids and or air from the chest cavity.

A more recent system that addresses some of the problems associated with the underwater drain is the three-bottle system in which a first bottle serves as a collection facility; a second bottle with an underwater inlet tube serves as the one-way valve; and a third bottle serves as a vacuum control bottle. The major advantages of this system are that the suction pressure can be controlled accurately and the opening pressure of the one-way valve remains constant.

A further development of the latter system is the integration of the three separate bottles into a single unit comprising three separate volumes. Some systems replace the third bottle with a mechanical valve which could be

P 1886PC00SιnapiChestDrain adjustable to control suction and some also replace the second bottle with a mechanical one-way valve. Nevertheless, the system remains bulky, expensive, and the water levels need to be checked regularly as the water in the unit evaporates.

Another solution to chest drainage is using a one way flutter valve, also called the Heimlich valve, in the form of a thin walled latex rubber or other flexible tube. The tubing collapses on itself at rest, but when positive pressure is applied to the device from the chest the tubing opens and air escapes. During inspiration, the tubing closes again, creating an effective one-way valve through which air can leave the chest but not re-enter. The major advantage of the Heimlich valve is that it allows greater mobility to the patient. However, the Heimlich valve on its own cannot be used where significant liquid drainage is expected and it cannot give an indication as to what the pleural pressure is at any time.

Another system uses a one-way valve similar to the Heimlich valve, but also has a flexible fluid collection bag. Whilst affording a patient greater mobility and allowing for significant fluid collection, low-pressure suction cannot be applied and in some devices the bag has to be replaced when full.

Various other mobile chest drainage solutions have also been developed, some having the function of detecting if air was currently exiting through the device. Air leaks have been detected using a small amount of water in a manometer type of arrangement in which bubbles indicate that air is exiting the device. Some devices also provide a pressure indicator that indicates when the pleural space pressure is larger or smaller than a set value in an attempt to verify that the fluid connection between the device and the pleural space is not blocked.

A major drawback of many of these devices is that it is not possible to apply low-pressure suction by way of them. Another problem is that only very small

PI 886PC00SinapiChestDraιn amounts of fluids can be collected in most of them before they need to be emptied. The emptying of some of these devices involves coupling a syringe to the device, without air going into the device during this procedure, and then extracting the liquids, and removing the syringe, again without air entering the device. The fluid filled syringe can be disposed of separately.

OBJECT OF THE INVENTION

It is an object of this invention to provide a chest drain that can be used to drain fluids from the thoracic space as and when appropriate; that can be used to apply suction as and when appropriate; that can be used in conjunction with external suction as and when appropriate; and that facilitates monitoring air leaks or lung expansion as and when appropriate.

SUMMARY OF THE INVENTION

In accordance with one aspect of this invention there is provided a chest drain comprising a liquid collection chamber having an inlet for connection to a chest drain tube and a vent outlet for operative venting to atmosphere or for connection to a source of vacuum, and a one-way valve for preventing backflow of fluids from the liquid collection chamber by way of the inlet, the chest drain being characterised in that the inlet has connected to it a variable volume elastomeric bulb in communication with the interior of the inlet and any tube supplying same.

Further features of this aspect of the invention provide for the elastomeric bulb to be connected in line with the inlet and tube supplying same, and for the elastomeric bulb to be selected such that it can be maintained in a collapsed condition by a vacuum of about 20 cm of water.

Preferably, the chest drain has an outlet chamber located within the liquid collection chamber and interposed between the collection chamber and vent

Pl 886PC00SinapiChestDrain outlet with a communication passage between the collection chamber and outlet chamber being arranged to inhibit entry of liquids collected into the outlet chamber, wherein the outlet chamber has at least one transparent wall and, in a generally upright orientation, includes a generally U-shaped duct adapted to retain a liquid, and wherein the liquid is capable of indicating a pressure difference between that in the communication passage and that in the vent outlet.

The U-shaped duct may be formed by a dividing wall within the outlet chamber wherein the dividing wall is perforated to allow controlled escape of gases through the outlet chamber without expulsion of the liquid in the U- shaped duct. The communication passage may comprise a larger and a coaxial smaller diameter transverse tube arranged to inhibit any liquid in the collection chamber from entering the outlet chamber irrespective of the orientation of the collection chamber. A baffle is preferably installed between the U-shaped duct and vent outlet from the outlet chamber.

In each instance, as a general rule, the collection chamber will have a drainage outlet typically controlled by way of a manually operable valve that preferably has an air inlet facility to allow for air to enter the collection chamber to replace liquid being drained from it.

In order that the above and other features of the invention may be more fully understood one embodiment of the both of the two different aspects thereof will now be described with reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:-

Figure 1 is a perspective view of one embodiment of chest drain according to the invention from one side thereof with the

Pl 886PC00SinapiChestDrain wall supporting the outlet chamber removed and illustrating schematically its practical application;

Figure 2 is the same perspective view of the chest drain from the other lateral side thereof;

Figure 3 is a schematic front view of the chest drain;

Figure 4 is a sectional view taken along line IV-IV in Figure 3;

Figure 5 is a sectional view taken along line V-V in Figure 3; and,

Figure 6 is a sectional view taken along line Vl-Vl in Figure 3.

DETAILED DESCRIPTION WITH REFERENCE TO THE DRAWINGS

In the embodiment of the invention illustrated in the drawings a chest drain is made of colourless transparent plastics mouldings and comprises a liquid collection chamber (1 ) of generally rectangular shape and having an inlet (2) at one side of what would generally be the top thereof for connection to a chest drain tube (3) which constitutes the tube supplying the inlet. This connection is effected by way of a variable volume elastomeric bulb (4) that is connected in line with the inlet and chest drain tube so that it is in communication with the interior of both the inlet and chest drain tube. Further detail of the elastomeric bulb will become apparent from what follows.

As schematically illustrated in Figure 1 , the chest drain tube would, in use, typically enter the pleural space of a patient and terminate in a catheter (5).

An appreciably smaller outlet chamber (6) is formed centrally on one major wall (7) of the collection chamber and a transverse communication passage (8) is formed at the top thereof to communicate between the interior of the

Pl 886PCQ0SinapiChestDrain collection chamber and the interior of the outlet chamber. That communication passage is formed, as shown in Figure 5, between a larger diameter tube (9) closed at one end (10) that is fixed to the wall of the collection chamber opposite that (7) supporting the outlet chamber and terminating short of the latter wall so as to be open at that end. A smaller diameter coaxial tube (11) is open at its end (12) corresponding to the closed end of the larger diameter tube and, at its other end, it extends transversely downwards into the interior of the outlet chamber. It will be understood that such a communication passage will substantially prevent any liquid from entering the outlet chamber as either one or other open end of the larger or smaller diameter tube would generally be above the liquid level.

The outlet chamber is divided vertically into two sub chambers by a dividing wall (13) with the smaller diameter coaxial tube (1 1) communicating with the sub chamber on one side of the dividing wall and a vent outlet (14) for operative venting to atmosphere or for connection to a source of vacuum communicating with the sub chamber on the other side of the dividing wall.

The dividing wall terminates short of the bottom of the outlet chamber so as to form a communicating slot (15) between the two sub chambers at the bottom. The wall of the sub chamber associated with the communications passage is roughly parallel to the dividing wall over its lower region. This provides a passageway (16) of approximately constant width at such lower region. Spaced upwardly from the lower edge of the dividing wall are two vertically spaced apertures (17) that allow gas to pass towards the vent outlet and create a pressure differential between the two sub chambers. The U- shaped duct formation and that includes the passageway (16) is adapted to retain a liquid in the manner of a manometer formed by a predetermined quantity of water indicated by waterline (18) (see Figure 3) introduced into the outlet chamber for the purpose to thereby indicate the pressure differential. An inclined baffle (19) is installed in the sub chamber associated

Pl 886PC00SιnapiChestDraιn with the vent outlet to prevent any water in the manometer formation from splashing into the vent outlet.

As indicated above, an elastomeric one-way valve is provided for preventing backflow of fluids from the liquid collection chamber by way of the inlet and back into the elastomeric bulb and chest drain tube. This one-way valve may be a duckbill style of one-way valve that requires about 20 mm of water pressure in order to open it and it can be associated with the inner end of the inlet to the collection chamber, a valve in such a position being indicated by numeral (20).

As an alternative, or in addition, the one-way valve could be attached to the end of the smaller diameter tube of the communication passage so that it is located within the first sub chamber of the outlet chamber and a valve is indicated in that position by numeral (21). The selection of the position for such a one-way valve depends on a number of considerations but, most importantly, a valve located at the inlet to the collection chamber would react more quickly whilst a valve in the outlet chamber is maintained in a cleaner state.

Finally, the collection chamber has a drainage outlet typically controlled by way of a manually operable valve (22) and such a valve preferably has an air inlet facility to allow for air to enter the collection chamber to replace liquid being drained from it.

In use, with the chest drain connected to a chest tube and catheter exiting a patient, fluid may flow from the patient and enter the collection chamber through the one-way valve (20) that preferably has an opening pressure of about 20mm of water when its internal surfaces are wetted. As fluid enters the collection chamber, air is driven through the communication passage to the first sub chamber of the outlet chamber. This air passes through the apertures (17) in the dividing wall and in so doing creates a pressure

Pl 886PC00SinapiChestDrain differential across the dividing wall and a consequential reading on the manometer formation in the passage (16). This provides an easily readable quantification of airflow from the patient. Flow entering the first sub chamber of the outlet chamber then exits the device through the vent outlet. A vacuum source may, of course, be applied to the vent outlet in the usual way.

Draining of the collection chamber can be achieved by disconnecting or clamping any vacuum tube and opening the manually operable valve (22) to allow the contents to drain into a disposal facility.

Turning now to the operation of the elastomeric bulb, an alternative method to quickly determine whether an air leak is present, is to simply depress the bulb and see if or how long it takes to pop out again. The bulb may also be used to create a vacuum / suction by pinching the chest drain tube above it, depressing the bulb, releasing the bulb and releasing the pinch. These steps can be repeated. This procedure is useful to generate a negative pressure when a patient is walking around and is thus not connected to a suction point. It may also be used to suck out possible blockages in the chest drain tube itself.

An additional function of the bulb is to reliably indicate whether there is in fact negative pressure in the catheter side of the device. An expanded bulb will serve as a warning to medical staff that there is either very little suction applied or the pressure is already positive.

It is to be mentioned that the collection chamber, being either totally transparent or at least having a transparent panel can be graduated with volume indicating marks on it. For measuring smaller quantities of liquid one corner of the generally rectangular collection chamber may be provided with volume indicating marks extending at a 45 degree angle to the horizontal to provides a user with a facility to tilt the device by 45 degrees from vertical so that the liquid runs into the corner.

P 1886PC00SιnapiChestDrain The chest drain could also be provided with a high negativity vent to ensure that a patient is never subjected to excessively high negative pressures. A spring loaded diaphragm is considered to be suitable for the purpose.

The chest drain could also be provided with a positive pressure release valve to ensure that a patient is never subjected to high positive pressures. Positive pressures may result if the air vent tube is occluded, the wall suction fails or the valve blocks.

Numerous variations may be made to the embodiment of the invention described above without departing from the scope hereof.

Pl 886PC00SinapiChestDrain

Claims

CLAIMS:

1. A chest drain comprising a liquid collection chamber (1) having an inlet (2) for connection to a chest drain tube (3) and a vent outlet (14) for operative venting to atmosphere or for connection to a source of vacuum, and a one-way valve (20, 21) for preventing backflow of fluids from the liquid collection chamber by way of the inlet, the chest drain being characterised in that the inlet has connected to it a variable volume elastomeric bulb (4) in communication with the interior of the inlet and any tube supplying same.

2. A chest drain as claimed in claim 1 in which the elastomeric bulb is connected in line with the inlet and tube supplying same.

3. A chest drain as claimed in either one of claims 1 or 2 in which the elastomeric bulb is selected such that it can be maintained in a collapsed condition by a vacuum of about 20 cm of water.

4. A chest drain as claimed in any one of the preceding claims in which the chest drain has an outlet chamber (6) located within the liquid collection chamber and interposed between the collection chamber and vent outlet with a communication passage (8) between the collection chamber and outlet chamber being arranged to inhibit entry of liquids collected into the outlet chamber, wherein the outlet chamber has at least one transparent wall (7) and, in a generally upright orientation, includes a generally U-shaped duct (6, 16) adapted to retain a liquid, and wherein the liquid is capable of indicating a pressure difference between that in the communication passage and that in the vent outlet (14).

5. A chest drain as claimed in claim 5 in which the U-shaped duct is formed by a dividing wall (13) within the outlet chamber wherein the

Pl 886PC00SιnapiChestDrain dividing wall is perforated (17) to allow controlled escape of gases through the outlet chamber without expulsion of liquid in the U-shaped duct.

6. A chest drain as claimed in either one of claims 4 or 5 in which the communication passage comprises a larger (9) and a coaxial smaller diameter (11 ) transverse tube arranged to inhibit any liquid in the collection chamber from entering the outlet chamber irrespective of the orientation of the collection chamber.

7. A chest drain as claimed in any one of claims 4 to 6 in which a baffle (19) is installed between the U-shaped duct and vent outlet from the outlet chamber.

8. A chest drain as claimed in any one of the preceding claims in which the collection chamber has a drainage outlet (22) typically controlled by way of a manually operable valve having an air inlet facility to allow for air to enter the collection chamber to replace liquid being drained from it.

Pl 886PCOOSinapιChestDrain